Signal and Indicator wiring
April 16th, 2013
One of the best descriptions of CTC signaling from both a modelers and prototype perspective that I am aware of may be found at the Control Train Components web site. There are several different options for wiring up signals and panel indicators for your model railroad. Normally these signals and indicators will use LEDs for illumination. We may cover options for incandescent lighted signals at a future time. The two primary options are to drive the LEDs directly from the Tower Controller outputs, and to use a driver card such as the 4ASD-4. Obviously the least cost option is to drive the LEDs directly as that saves the cost of an extra board. However, in some cases the extra board is justified or even required.
Signal arm or signal head = Each individual signal unit
Aspect = The speed or route indication given by one or more signal
heads or arms.
Marker = A signal head or arm that does not change color or position.
Light = The individual lamp in a signal. A light may indicate multiple
aspects if it changes color like a searchlight signal, or it may take
multiple lights to indicate a single aspect, for example in position
light signals.
Mast = The pole that mounts one or more signal arms that (usually)
control each individual track.
Single connectors are shown in these schematic drawings, but
normally each signal mast will have its own connector spaced out along
a single ribbon cable coming from each port or driver card.
The TC-64 outputs may be used to directly drive LEDs as long as external resistors are used to prevent over current. These circuits show only one polarity of wiring, but each may be reversed by inverting the LEDs and changing the common wire connections.
In situations where more voltage is required to drive several LEDs in series the 4ASD-4 board provides 9V to the signal drive circuits. This board also includes on board current limiting resistors and multiplexed outputs to allow up to 4 heads to be controlled with each 10 wire ribbon cable.
On board jumpers allow the fourth aspect to be either always illuminated, (Marker) or else controlled by the 'Dark' aspect of the signal. (Coded) If the signal is being used with 4 lighted aspects mode, then it may never be dark. Note: 'Marker' is not considered a coded aspect, so signal heads with an additional marker lamp may also show dark or flashing aspects on the main head.
The Signalman is a new stand alone signal driver board. It accepts either turnout commands or the NMRA signal accessory decoder commands for its operation. It may be operated directly from a DCC supply, or from a LocoNet compatible serial bus. It may be controlled with either NMRA DCC signal accessory decoder commands or DCC turnout commands. Like the 4ASD-4 and LNCP it has more voltage available in order to drive several LEDs in series. The SignalMan includes internal resistors that provide up to 20 ma. per lamp. The SignalMan also includes CV controlled PWM brightness settings that can cut the brightness of each individual lamp as required. The SignalMan is designed to be located close to the signals that it controls and be directly connected. Therefore it does not include any multiplexing which makes for easier wiring connections. The SignalMan is fully programmable to support nearly any signal system with up to 4 lamps per aspect.
SignalMan is expected to be available in the summer of 2013.
The SHD-2 board was concieved by Team Digital and is built by RR-CirKits. It is a very small basic NMRA signal head decoder. It drives two signal heads with steady or flashing lamps. It may be controlled with either NMRA DCC signal accessory decoder commands or DCC turnout commands. The SHD-2 includes internal resistors that provide up to 20 ma. per lamp. The SHD-2 also includes CV controlled PWM brightness settings that can cut the brightness of each individual lamp as required. The SHD-2 is designed to be located close to the signals that it controls and be directly connected. Therefore it does not include any multiplexing which makes for easier wiring connections. The SHD-2 uses 5VDC and is limited to driving single LED per aspect signals.
SHD-2 is expected to be available in the summer of 2013.